In many settings it is desirable to have a control system that allows for convenient control of water faucets and other water delivery fixtures. Touchless control systems have been developed which allow water flow from a faucet when a person places his or her hand within range of an infrared sensor. Touchless control systems promote sanitary conditions because they eliminate the need to touch any part of the faucet. Many touchless control systems, however, lack a means for convenient adjustment of water temperature. The ability to adjust temperature is indispensable in households, hotels, hospitals, and many work places. Touchless control systems that have no temperature control can be installed to dispense only warm water, for example, but this increases energy costs when warm water is not needed. Or the system can be set to dispense only cold water, but this can be quite unpleasant during winter months. Neither setting is appropriate where sometimes cold water is desired, such as for waking up or cooling off on a hot day, but at other times hot water is required in order to kill bacteria.
Another drawback of existing faucet control systems is that installation often requires replacement of the faucet spout, which makes retrofitting of existing washrooms expensive. Retrofitting is further complicated when removal of conventional hot and water control knobs on either side of the faucet spout exposes unsightly holes on a countertop. Installing caps with no other purpose than to cover the holes is often undesirable, such as in luxury hotels and other  locations where a finished appearance is important, because such caps draw attention to the fact that a retrofit was performed.
Persons skilled in the art have recognized a need for a system and method for controlling water temperature to reduce water waste, conserve energy, and promote sanitary conditions. There is also a need for a system and method which reduces the expense of retrofitting existing washrooms. There is also a need for a faucet control system and method that allows for flexibility in placement of a temperature or water flow control in order to accommodate use by a broad range of persons. The present invention satisfies these and other needs.